[AMRadio] Odd tuning on 160M


M. K. Hess mkhess at kias.org
Sat Jul 18 13:16:50 EDT 2009


Hi Folks,

Here's a question that may need to get filed under "dumb", or maybe not, but
here goes!

I have a V-Beam, a Vertical, and a Dipole, all capable of 160M operation. I
use a K3 as my exciter, an Alpha 91B as an Amp, and
a Palstar AT-Auto for the tuner. The following happens with any of these
antennas, including my dummy load (Heath CanTenna)...

I have the Alpha in Stby, and key up the K3 w/ 10w through the Palstar to
"whatever" load.... If finds a 1:1 match and all is well.
If I advance the K3 to 120W all remains well... Can Xmit all day and night,
without issue. NOW....

I fire up the Alpha 91B, and begin to tune it.... after a couple of seconds,
the Palstar starts to "re-tune" the load. I wait until it settles, and 
start the Alpha load again, same thing... this happens a few times until
finally the Palstar thinks it's got a match, AND the Alpha thinks it's
happily loaded...

Finally, I hear someone calling.... I call back... as I'm talking, the
Palstar starts re-tuning again and the Alpha usually goes into Hi-SWR
shutdown...
I fiddle with them for a bit, and try the call again.... Sometimes it stays
stable, most times it goes haywire several times during the QSO...

WTF is going on!?!?!?!

I have grounding out the ying-yang, and no RF back to the station, I have
heavy duty parts from the shack to the antennas.. (See my web www.n3eaq.net
for details)
This mostly seems to happen on 160 and 80 and DEFINITELY on 1885 when I'm
trying to do AM!

Any ideas!?!?!?! All help is appreciated!

Mike - N3EAQ



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